import math
class Circle:
    def __init__(self,r):
        self.radius =r
    def get_perimeter(self):
        perimeter = 2*math.pi*self.radius
        return  perimeter
    def get_area(self):
        area = math.pi * self.radius*self.radius
        return area
circle = Circle(4)
per = circle.get_perimeter()
area = circle.get_area()
print(f"周长为：{per:.2f}")
print(f"面积：{area:.2f}")